Various techniques are known for insulation and/or drainage, and in general each is adapted to the type of building and/or ground concerned, and at least for insulating walls, they make use of materials that are essentially artificial and/or natural, but that are reconstituted.
Thus, to insulate the outside vertical walls of a building, the inside surfaces thereof are generally lined with large sheets of plaster-board type material, or indeed of wood, or a genuine double partition is made of bricks or other stacked building materials, leaving a gap which is preferably filled with insulating material of the polystyrene type or of the rock or glass wool type, etc.
There also exist building materials that are themselves made up of various layers of material, some of which constitute a load-bearing core of the wall built up using such materials, while the others provide insulation, however that is suitable for use only in new buildings, and represents a manufacturing cost and an insulation cost that are relatively high.
Such techniques are indeed effective, at least so far as insulation is concerned, but they often need to be used together with other techniques to combat, in particular, damp, which often also reduces the lifetime and the effectiveness of techniques used for insulation purposes, or at least spoils the appearance of the materials used. Thus, no building material or method or technique is suitable for being used on its own directly for various applications such as insulating outside walls, floors, and foundations of outside walls, and more particularly none is suitable in the field of drainage.
When draining ground, in particular either near the foundations of a building, or a plot from which it is desired to recover water, or at least collect it for disposal elsewhere, after the water has infiltrated through the ground, the techniques generally used are of the type whereby trenches are dug around the structure to be protected, for example, and then filled with pebbles or other granular or powder materials which are poured in in bulk. It is thus possible to use a combination of layers of said pebbles or other material, overlying pipes that are pierced with orifices and that are laid at the bottoms of the trenches. In most cases, in order to prevent the drainage pipes and/or the inter-grain gaps in the material with which such a trench is filled from becoming clogged by earth entrained by water running from the surrounding plot which is to be drained or merely dried out in order to protect a building, the trench is lined, or at least that wall of said trench which is adjacent to the plot is lined prior to the pipes and/or the pebbles being put into place, the lining material being sheets of porous flexible material where porosity is ensured either by the material being woven or else by perforations.
Nevertheless, not only is it difficult to hold such sheets of flexible material against the walls of the trench while it is being filled, which in the case of collapse (rather frequent) reduces the effectiveness thereof, but also it is difficult to perform the work, since the use of pebbles or other heavy materials requires handling and transport equipment that is heavy and slow to operate, thereby increasing the cost of the operation. Extracting pebbles from quarries in rivers is an activity that is becoming more and more controlled and restricted.